The simians are sister group to thetarsiers (Tarsiiformes), together forming thehaplorhines. The radiation occurred about 60 million years ago (during theCenozoic era); 40 million years ago, simians colonizedSouth America, giving rise to theNew World monkeys. The remaining simians (catarrhines) split about 25 million years ago intoCercopithecidae andapes (includinghumans).
In earlier classification, New World monkeys, Old World monkeys, apes, and humans – collectively known assimians oranthropoids – were grouped underAnthropoidea (/ˌænθrəˈpɔɪdi.ə/; from Ancient Greekἄνθρωπος (ánthrōpos)'human' and -οειδής (-oeidḗs)'resembling, connected to, etc.'), while thestrepsirrhines and tarsiers were grouped under the suborder "Prosimii". Under modern classification, the tarsiers and simians are grouped under the suborderHaplorhini, while the strepsirrhines are placed in suborder Strepsirrhini.[5] Strong genetic evidence for this is that fiveSINEs are common to all haplorhines whilst absent in strepsirrhines — even one being coincidental between tarsiers and simians would be quite unlikely.[6] Despite this preferred taxonomic division, "prosimian" is still regularly found in textbooks and the academic literature because of familiarity, a condition likened to the use of themetric system in the sciences and the use ofcustomary units elsewhere in the United States.[7] In the Anthropoidea, evidence indicates that the Old World and New World primates went through parallel evolution.[8]
Primatology,paleoanthropology, and other related fields are split on their usage of the synonymous infraorder names, Simiiformes and Anthropoidea. According toRobert Hoffstetter (and supported byColin Groves), the term Simiiformes haspriority over Anthropoidea because the taxonomic termSimii byvan der Hoeven, from which it is constructed, dates to 1833.[1][9] In contrast, Anthropoidea byMivart dates to 1864,[10] while Simiiformes byHaeckel dates to 1866, leading to counterclaims of priority.[1] Hoffstetter also argued that Simiiformes is also constructed like a proper infraorder name (ending in "iformes"), whereas Anthropoidea ends in -"oidea", which is reserved for superfamilies. He also noted that Anthropoidea is too easily confused with "anthropoïdes", which translates to "apes" from several languages.[9]
Some lines of extinct simian also are either placed into theEosimiidae (to reflect theirEocene origin) and sometimes inAmphipithecidae, thought to originate in theEarly Oligocene. Additionally,Phileosimias is sometimes placed in the Eosimiidae and sometimes categorised separately.[11]
The origin of anthropoid primates was initially thought to be Africa, however, fossil evidence, now suggests they originated in Asia. During the middle to lateEocene, multiple groups of Asian anthropoids crossed theTethys Sea on natural rafts or floating islands, colonizing Africa alongside other Asian mammals. The earliest African anthropoid fossils appear in sites across northern Africa, including Algeria, Libya, and Egypt. This dispersal before Africa and Asia were connected by land was aided by size, Asian monsoons, and river systems. After reaching Africa, anthropoids underwent major evolutionary changes, with some groups later crossing the South Atlantic to establish the New World monkey lineage in South America.[12]
The New World monkeys in parvorder Platyrrhini split from the rest of the simian line about 40 million years ago (mya), leaving the parvorder Catarrhini occupying the Old World. This latter group split about 25 mya between theCercopithecidae and the apes, making Cercopithecidae more closely related to the apes than to the Platyrrhini.
Below is a cladogram with some of the extinct simian species with the more modern species emerging within the Eosimiidae. The simians originated in Asia, while the crown simians were in Afro-Arabia.[13][14][5][15][7][16] It is indicated approximately how many Mya the clades diverged into newer clades.
Dolichocebus annectens andParvimico materdei would normally, given their South American location and their age and other factors, be considered Platyrrhini. The original Eosmiidae appear polyphyletic withNosmips,Bahinia, andPhileosimias at different locations from other eosimians.
In a section of their 2010 assessment of the evolution of anthropoids (simians) entitled "What is an Anthropoid", Williams, Kay, and Kirk set outa list of biological features common to all or most anthropoids, including genetic similarities, similarities in eye location and the muscles close to the eyes, internal similarities between ears, dental similarities, and similarities on foot bone structure.[6] The earliest anthropoids were small primates with varied diets, forward-facing eyes, acute color vision for daytime lifestyles, and brains devoted more to vision and less to smell.[6] Living simians in both the New World and the Old World have larger brains than other primates, but they evolved these larger brains independently.[6]
Simians characteristically have relatively large brains, fused mandibles, binocular and color vision, and the females have a single fused uterus.[20] They also have fewer teeth and are more sexually dimorphic in terms of body size and anatomy.
The traits that separate New World simians from Old World simians are the nostrils and their dentation. New World simians have broad noses with forward facing nostrils and three premolars in each quadrant of the mouth, while Old World simians have narrower noses with downward facing nostrils and a narrow septum and only have two premolars.[citation needed]
^abRylands AB, Mittermeier RA (2009). "The Diversity of the New World Primates (Platyrrhini)". In Garber PA, Estrada A, Bicca-Marques JC, Heymann EW,Strier KB (eds.).South American Primates: Comparative Perspectives in the Study of Behavior, Ecology, and Conservation. Springer.ISBN978-0-387-78704-6.
^abHartwig, W. (2011). "Chapter 3: Primate evolution". In Campbell, C. J.; Fuentes, A.; MacKinnon, K. C.; Bearder, S. K.; Stumpf, R. M (eds.).Primates in Perspective (2nd ed.). Oxford University Press. pp. 19–31.ISBN978-0-19-539043-8.
^Lull, Richard Swann (1917). "XXXVII: The Evolution of Man".Organic Evolution (1929 ed.). New York: The Macmillan Company. pp. 641–86 – via Google Books.
_(white_background)_(1).jpg)
_(white_background).jpg)
